On the Internet,
you can pay bills, rack up more bills, look up an address or hunt for a
new house.

And now you can add
another Web-based task: Volunteer your DNA for the good of science.

In recent months,
at least three Web sites have begun seeking blood or saliva for DNA analysis.

Proponents say it's
the only way to recruit the thousands of individuals needed to identify
subtle variations in DNA that might increase one's susceptibility to a
disease. Toward that goal, they want to compare DNA from people who have
a disease with DNA from people who don't have it. By identifying differences,
they hope to develop new drugs or diagnostic tests.

Like any Web-based
enterprise, these sites raise concerns about privacy, although their backers
say they have gone to great lengths to protect people's identities. The
privacy issue aside, skeptics question whether studying subjects who are
recruited willy-nilly through the Internet will ever lead to useful discoveries.

Although its Web
site has been up since last summer, Brussels-basedSpitters.com is ''still
sorting out some things on the privacy thing,'' spokeswoman Catherine van
Gerven says. Still, she says, the site already has attracted saliva samples
from a few thousand Web surfers.

Until now, DNAPrint
Genomics, which is looking for genetic variations that might affect how
people react to medications, had collected blood samples only at Florida
blood donation centers and doctors' offices, says Tony Frudakis, head of
the Sarasota company.

At the urging of
participating physicians, Frudakis' company has now placed its informed-consent
form and medical questionnaire online. Out-of-state residents can request
a saliva collection kit.

The most publicized
site, DNA Sciences' Gene Trust, has registered 7,500 people in the USA
since its launch last summer, says Hugh Reinhoff, founder and head of DNA
Sciences in Mountain View, Calif.

Those volunteers
have completed one or two surveys about their health and medical history
and have been deemed of interest to DNA Sciences, which is focusing on
breast cancer, colon cancer, multiple sclerosis and type 2 (or adult-onset)
diabetes. The next step: a visit by a phlebotomist to draw blood.

Joseph Terwilliger
of Columbia University's Genome Center likens seeking significant variations
in randomly collected DNA to looking for a needle in a stack of needles.

One problem, Terwilliger
says, is that medical information supplied by volunteers recruited online
is unlikely to be highly accurate -- a problem when the whole point of
the research is to find disease-related genetic variations.

Of even greater concern,
Terwilliger says, is an overemphasis on the role of genes in disease, which
is often weak at best.